California Code, Penal Code - PEN § 3041.2

(a) During the 30 days following the granting, denial, revocation, or suspension by the board of the parole of an inmate sentenced to an indeterminate prison term based upon a conviction of murder, the Governor, when reviewing the board's decision pursuant to subdivision (b) of Section 8 of Article V of the Constitution, shall review materials provided by the board.

(b) If the Governor decides to reverse or modify a parole decision of the board pursuant to subdivision (b) of Section 8 of Article V of the Constitution, he or she shall send a written statement to the inmate specifying the reasons for his or her decision.